A disc cartridge includes, for example, a disc cartridge shown in Japanese Unexamined Patent Application Publication No. 2003-109343 and a disc cartridge shown in Japanese Unexamined Patent Application Publication No. 2005-78675 The disc cartridge shown in Japanese Unexamined Patent Application Publication No. 2003-109343 is a standard size disc cartridge using an optical disc having a diameter of 12 cm as a recording medium, and the disc cartridge shown in Japanese Unexamined Patent Application Publication No. 2005-78675 is a small size disc cartridge using an optical disc having a diameter of 8 cm as a recording medium. Since compatibility is established between these two disc cartridges by employing a common recording format to the optical discs, information signals can be recorded and/or replayed by a common recording and/or replaying device.
The standard size disc cartridge of Japanese Unexamined Patent Application Publication No. 2003-109343 includes a cartridge main body, an inner rotor acting as a rotation wheel, and a pair of shutter plates. The cartridge main body has a first opening formed to a bottom surface for recording and/or replaying, the inner rotor is rotatably accommodated in the cartridge main body as well as accommodates an optical disc and has a second opening formed thereto in correspondence to the first opening of the cartridge main body so that the optical disc can be faced to the outside therethrough and the pair of shutter plates are interposed between the bottom surface of the cartridge main body and the inner rotor and turned in association with the rotation of the inner rotor and release the first opening and the second opening when they coincide with each other. Further, the standard size disc cartridge includes a locking mechanism for locking the pair of shutter plates by locking the rotation of the inner rotor in a state that they close the first and second openings.
The locking mechanism has a locking member for locking the inner rotor. The locking member is turnably mounted on a support shaft formed on the inner surface of the cartridge main body, has a locking portion as a stopper piece formed thereto so as to be in sliding contact with the outer peripheral portion of the inner rotor and a unlocking portion formed thereto. The unlocking portion is composed of a manipulating projection facing the outside from a side surface of the cartridge main body.
When the disc cartridge is inserted into a recording and/or replaying device, the unlocking portion of the locking member is depressed by a rack rod on the recording and/or replaying device side, the locking member is turned thereby, and the locking portion is separated from the outer peripheral portion of the inner rotor so that the inner rotor is placed in a rotatable state. Next, as the disc cartridge is transported to a recording and/or replaying position, the inner rotor is rotated by the rack rod meshed with a gear, and the pair of shutter plates is also turned in association with the rotation of the inner rotor. Then, when the first opening of the cartridge main body coincides with the second opening of the inner rotor at a recording and/or replaying position, the disc cartridge is placed in a recording/replaying possible state with its optical disc facing to the outside.
Further, the small size disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675 also has approximately the same arrangement as the disc cartridge of Japanese Unexamined Patent Application Publication No. 2003-109343 described above. That is, the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675 has a rotation wheel corresponding to an inner rotor and rotatably accommodated in a cartridge main body, and a pair of shutter plates is interposed between the rotation wheel and the cartridge main body.
In the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675, a locking mechanism is arranged differently from the locking mechanism of the disc cartridge of Japanese Unexamined Patent Application Publication No. 2003-109343 described above. That is, the locking mechanism in the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675 has a locking member for locking the rotation wheel. The locking member is turnably mounted on a support shaft formed to the inner surface of a lower shell constituting a cartridge main body, and has a locking portion formed thereto so that it is engaged with an engaging recessed portion formed to the outer peripheral portion of the rotation wheel. Further, the locking member has an unlocking piece. The unlocking piece is faced to one of groove portions formed to the vicinity of both the corner portions of the front surface of the cartridge main body acting as an insertion edge to a recording and/or replaying device.
When the disc cartridge of the Japanese Unexamined Patent Application Publication No. 2005-78675 is inserted into the recording and/or replaying device, the unlocking member enters one of the groove portions of the front surface of the cartridge main body and depresses the unlocking piece of the locking member, thereby the locking member is turned, the locking portion of locking member is disengaged from the engaging recessed portion of the rotation wheel, and thus the rotation wheel is placed in a rotatable state. When the rotation wheel is rotated, the pair of shutter plates is also turned in association with the rotation of the rotation wheel, and the first opening of the cartridge main body coincides with the second opening of the rotation wheel at the recording and/or replaying position, thereby the disc cartridge is placed in a recording/replaying possible state with its optical disc facing to the outside.
Incidentally, in the small size disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675, the groove portions formed to both the sides of the front surface acting as the insertion edge to the recording and/or replaying device are act as insertion guide grooves when the disc cartridge is inserted into a recording and/or replaying device commonly used with the disc cartridge of Japanese Unexamined Patent Application Publication No. 2003-109343. That is, in the recording and/or replaying device in which the disc cartridge of Japanese Unexamined Patent Application Publication No. 2003-109343 and the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675 can be mounted, when it is intended to position the two disc cartridges using location holes and alignment holes formed to the bottom surfaces of them, positioning pins corresponding to the positions of the location holes and the alignment holes of the respective disc cartridges must be provided. In this case, the positioning pins corresponding to the small size disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675 are disposed inward of the positioning pins of the disc cartridge of Japanese Unexamined Patent Application Publication No. 2003-109343. However, when the positioning pins for the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675 are disposed, they interfere with the disc cartridge of Japanese Unexamined Patent Application Publication No. 2003-109343. To overcome the problem, it is necessary to provide a positioning pin moving mechanism for the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675 and to retract the positioning pins for the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675 when the disc cartridge of Japanese Unexamined Patent Application Publication No. 2003-109343 is mounted to prevent them from interfering with the disc cartridge of Japanese Unexamined Patent Application Publication No. 2003-109343. However, provision of the moving mechanism makes the arrangement of the recording and/or replaying device complex. Accordingly, in the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675, the shutters are unlocked as well as positioning is carried out by engaging the positioning pins with the groove portions formed to both the sides of the front surface acting as the insertion edge to the recording and/or replaying device. That is, position can be carried out using the pair of the groove portions on the front surface without using the location hole and the alignment hole on the bottom surface of the cartridge main body.
However, since even the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675 is designed such that it is positioned using the location hole and the alignment hole when it is mounted on the recording and/or replaying device, it is preferable to position the disc cartridge using the location hole and the alignment hole as much as possible. This is because when the disc cartridge is positioned using the groove portions, an error may occur to a mounting position.
Accordingly, when the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675 is positioned in a recording and/or replaying device dedicated for the disc cartridge of Japanese Unexamined Patent Application Publication No. 2005-78675, it is preferable to position it using a location hole and an alignment hole on the bottom surface of a cartridge main body because a positioning accuracy is also improved.
Accordingly, an object of the present invention, which was made in view of the above problems, is to provide a disc cartridge capable of unlocking shutter plates at a plurality of positions so that a dedicated recording and/or replaying device and a recording and/or replaying device commonly used with a standard size disc cartridge can be easily designed with a simplified arrangement.